Freewheel flow track systems

ABSTRACT

Freewheel flow track systems are adapted for transporting pallets and/or cartons in heavy-duty pallet and carton flow applications. A flow track system may include multiple track sub-assemblies, each track sub-assembly including multiple wheel assemblies. Each wheel assembly comprises a wheel rotatably mounted on an axle. A lubricant coating may be fixed to and bonded with the axle. The wheel may be constructed from a polycarbonate-based resin that is impregnated with a lubricant for providing lifetime lubrication to the wheels. The wheel includes a hub, a rim concentric with the hub, a web connecting the hub to the rim, and ribs connecting the hub to the rim through the web.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. Nonprovisionalapplication Ser. No. 10/857,184 entitled “Freewheel Flow Track Systems,”filed May 28, 2004, which is a divisional of U.S. Nonprovisionalapplication Ser. No. 09/956,253 entitled “Freewheel Flow Track Systems,”filed Sep. 20, 2001, now abandoned, which claims the benefit of U.S.Provisional Application No. 60/234,568 entitled “Pallet ConveyingSystem,” filed Sep. 22, 2000, each of which is hereby incorporated byreference.

BACKGROUND

The steel wheel track system, or skate wheel track system, is one of themost commonly used flow track systems in the material handling industry.The steel wheel track system comprises a track assembly including one ormore parallel track frames. Each track frame includes a pair of parallelsteel frame members, also known as “profiles”, and multiple wheelassemblies mounted between the profiles. Each wheel assembly includes asteel wheel rotatably mounted on an axle that extends between theprofiles transverse to the track flow direction. The wheels aretypically 1.9 inches in diameter and 0.50 inches to 0.56 inches inwidth. The wheels comprise steel outer shells having thicknesses between22 gage and 13 gage, depending upon the particular application in whichthe wheels are used. Additionally, a number of ball bearings are used inthe wheels to increase the load capacity of the wheels and to enable thewheels to roll. Each wheel will typically have between six and twelveball bearings. The load capacity of a skate wheel can vary betweentwenty-five pounds to one hundred-fifty pounds, depending on thethickness of the shell and the number of bearings the wheel contains.

Steel wheel track systems are predominantly used in pickingapplications. Picking applications are applications in which a loadedwooden pallet is placed on the track assembly at an entrance end of thetrack assembly, rolled forward to an exit end of the track assembly andthen presented to a picker that takes cartons off the pallet for orderpicking and shipping to stores or other locations. Steel wheel tracksystems are also used in applications in which cartons are placeddirectly on the track assembly and rolled from an entrance end of thetrack assembly to an exit end of the track assembly.

There are several problems that occur with existing steel wheel tracksystems. One problem occurs because the pallets used in pickingoperations are sometimes low quality pallets that have broken bottomboards and/or soft, damaged wood. Due to the narrowness of the steelwheels presently used (only 0.50 inches to 0.56 inches wide), the wheelstend to get caught by broken boards or embed themselves in soft wood.Likewise, when damaged cartons are transported directly on a trackassembly, the wheels tend to embed themselves in damaged sections of thecartons. In such situations, a picking operator must pull the pallet orcarton towards the exit end of the track assembly using a tool called ashepherd's hook. In doing so, the operator must often exert high forcesto keep the pallet moving towards the exit end of the track assembly. Asa result, operators have slipped, fallen and sustained injuries whileusing shepherd's tools to move pallets.

Another problem occurs when low quality pallets are used. When a skatewheel track is designed, consideration is given to the loads that theskate wheels must support. The load that each wheel supports is a factorof the load being carried by the pallets, the length of the pallets usedand the number of wheels on the track assembly for a given length (thus,the number of wheels supporting the pallet). Based on the load, thelength of the pallets and the number of wheels for a given length, therequired load capacity for each wheel can be calculated. A particularwheel design (i.e., outer shell thickness and number of bearings) can beselected. However, the wheels are subjected to unusually high loads whena pallet is used that is missing a front or a back board, or that isotherwise shorter than the pallets the tracking system is designed tocarry. This is due to the fact that a fewer number of wheels support theshorter pallet. The wheels may not be capable of supporting the elevatedloads and may break, requiring the picking operator to use a shepherd'stool to move the pallets forward along the track assembly. As statedbefore, this can result in injury to the picking operator.

Yet another problem exists with present steel wheel track systems. Manyflow systems, such as those in environments that are subject to FDAcleanliness requirements, require washdowns. However, the steel wheelsused in present flow track systems are susceptible to corrosion. Thus,frequent washdowns can damage steel wheels and cap eventually renderthem inoperable.

It is an object of the present invention to provide a flow track systemthat will allow pallets and cartons to flow reliably, efficiently, andin a way that is safe for picking operators. It is a further object ofthe invention to provide a flow track system that can be used inenvironments that require washdowns.

SUMMARY

The present invention discloses Freewheel Flow Track Systems fortransporting pallets and/or cartons in heavy-duty pallet and carton flowapplications. According to certain embodiments of the invention, a flowtrack system comprising multiple, longitudinally extending, paralleltrack sub-assemblies is disclosed. Each track sub-assembly includes atrack frame comprising a pair of parallel profiles, and multiple wheelassemblies connected to the pair of profiles and arranged in a rowextending from an entrance end of the track assembly to an exit end ofthe track assembly. The wheel assemblies each comprise an axle extendingbetween the pair of profiles and a polycarbonate resin wheel rotatablymounted on the axle.

A lubricant coating is fixed to and bonded with the axle. Thepolycarbonate resin wheels are constructed from a polycarbonate-basedresin that is impregnated with a lubricant for providing lifetimelubrication to the wheels. The lubricant in the wheels and the lubricantcoating of the axles give the wheel assemblies a low coefficient offriction, high rollability and high durability. The wheels each includea hub, a rim that is concentric with the hub, a web that connects thehub to the rim and ribs that connect the hub to the rim through the web.The wheel assemblies are self-lubricating and are of high strength fortransporting heavy pallets and cartons.

According to other embodiments of the invention, a flow track systemincluding a single track assembly suitable for directly supportingcartons is disclosed. The track assembly includes a wide track frame.The track frame includes a pair of parallel profiles and multiple wheelassemblies connected to the profiles and arranged in a row extendingfrom an entrance end of the track assembly to an exit end of the trackassembly. In this embodiment, each wheel assembly includes an axleextending between the profiles and a multiple wheels rotatably mountedon the axle in a row extending transverse to the track flow direction.

The freewheel flow track systems disclosed by the invention providereliable, efficient and safe pallet and carton flow. The flow trackassemblies disclosed by the present invention are more durable andrequire less maintenance than existing flow track systems. Inparticular, the wheel assemblies of the present invention areself-lubricating, and the polycarbonate wheels are stronger and widerthan conventional track wheels to avoid overloading problems and flowproblems typically caused by damaged or irregular pallets and cartons.Other features and advantages of the present invention will be apparentto those of skill in the art upon reading and understanding thefollowing detailed description of the invention, drawings and claims.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a cut-away top view of a freewheel flow track systemaccording to one embodiment of the invention.

FIG. 2 shows a cut-away side view of the freewheel flow track system ofFIG. 1.

FIG. 3 shows a view of a track subassembly of FIG. 2 taken along sectionB-B.

FIG. 4 shows a partial side view of a first profile of the freewheelflow track system of FIG. 1.

FIG. 5 shows a partial bottom view the profile of FIG. 4.

FIG. 6 shows a view of the profile of FIG. 4, taken along section K-K.

FIG. 7 shows a partial side view of a second profile of the freewheelflow track system of FIG. 1.

FIG. 8 shows a partial bottom view the profile of FIG. 7.

FIG. 9 shows a view of the profile of FIG. 7, taken along section L-L.

FIG. 10 shows a first view of a wheel for a freewheel flow track system.

FIG. 11 shows a second view of the wheel of FIG. 10.

FIG. 12 shows an end view of the wheel of FIG. 10.

FIG. 13 shows a transparent end view of the wheel of FIG. 10.

FIG. 14 shows views of two sides of the wheel of FIG. 10.

FIG. 15 shows a view of the wheel of FIG. 14 taken along section A-A.

FIG. 16 shows a view of the wheel of FIG. 14 taken along section C-C.

FIG. 17 shows a cut-away top view of a freewheel flow track systemaccording to another embodiment of the invention.

FIG. 18 shows a cut-away side view of the freewheel flow track system ofFIG. 17.

FIG. 19 shows a view of a track sub-assembly of FIG. 18 taken alongsection D-D.

FIG. 20 shows a cut-away top view of a freewheel flow track systemaccording to another embodiment of the invention.

FIG. 21 shows a cut-away side view of the freewheel flow track system ofFIG. 20.

FIG. 22 shows a view of a track sub-assembly of FIG. 21 taken alongsection B-B.

FIG. 23 shows a partial side view of a first profile of the freewheelflow track system of FIG. 20.

FIG. 24 shows a partial bottom view the profile of FIG. 23.

FIG. 25 shows a view of the profile of FIG. 23, taken along section M-M.

FIG. 26 shows a partial side view of a second profile of the freewheelflow track system of FIG. 20.

FIG. 27 shows a partial bottom view the profile of FIG. 26.

FIG. 28 shows a view of the profile of FIG. 26, taken along section N-N.

FIG. 29 shows a top view of a freewheel flow track system according toanother embodiment of the invention.

FIG. 30 shows a side view of the freewheel flow track system of FIG. 29.

FIG. 31 shows a view of a track sub-assembly of FIG. 30 taken alongsection F-F.

FIG. 32 shows a cut-away top view of a freewheel track system accordingto yet another embodiment of the invention.

FIG. 33 shows a cut-away side view of the freewheel track system of FIG.32.

FIG. 34 shows a view of a track assembly of the freewheel system of FIG.33 taken along section G-G.

FIG. 35 shows a cut-away top view of a freewheel track system accordingto another embodiment of the invention.

FIG. 36 shows a cut-away side view of the freewheel track system of FIG.35.

FIG. 37 shows a view of a track assembly of the freewheel system of FIG.36 taken along section H-H.

FIG. 38 shows a cut-away top view of a freewheel track system accordingto yet another embodiment of the invention.

FIG. 39 shows a cut-away side view of the freewheel track system of FIG.38.

FIG. 40 shows a view of a track assembly of the freewheel system of FIG.39 taken along section I-I.

FIG. 41 shows a cut-away top view of a freewheel track system accordingto yet another embodiment of the invention.

FIG. 42 shows a cut-away side view of the freewheel track system of FIG.41.

FIG. 43 shows a view of a track assembly of the freewheel system of FIG.42 taken along section J-J.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, in which like numerals represent likecomponents throughout the several views, FIGS. 1 and 2 show cut-awayrepresentations of a Freewheel Flow Track System 1 according to apreferred embodiment of the invention. FIG. 1 shows a cutaway view ofthe freewheel flow track system 1 including a track assembly 2 having anentrance end 3 and an exit end 4. Products supported by the trackassembly 2 are transported in a track flow direction extending from theentrance end 3 to the exit end 4. The track assembly 2 comprises threeparallel track sub-assemblies 2 l, 2 c and 2 r extending longitudinallyfrom the entrance end 3 to the exit end 4, wherein the tracksub-assemblies 2 l, 2 c and 2 r are left, center and right subassemblies, as viewed from exit end 4. It should be understood that,although the track system 1 is shown with three track sub-assemblies, itis possible for track systems to include fewer than three tracksub-assemblies or more than three track sub-assemblies, as required bythe loads transported by the system. For example, track sub-assembly 2 cmay be eliminated in certain applications, such that only two tracksub-assemblies 2 l and 2 r are utilized. Continuing, the tracksub-assemblies 2 l, 2 c and 2 r are supported by an underlying supportstructure (not shown), typically (though not necessarily) in an inclinedorientation. The track sub-assemblies 2 l, 2 c and 2 r each include atrack frame 10 and wheel assemblies 30 mounted to the respective trackframe 10 for maintaining rolling engagement with a wooden pallet 5. Thewheel assemblies of each track sub-assembly 2 l, 2 c and 2 r arearranged in a row extending from the entrance end 3 to the exit end 4.

A wooden pallet 5 is shown supported by the track assembly 2. The pallet5 is representative of one type of pallet commonly used in pickingapplications and includes three transversely extending top boards 6 a, 6b and 6 c, three longitudinally extending pallet stringers 7 a, 7 b and7 c, and three transversely extending bottom boards, which are hiddenfrom view by the top boards 6 a, 6 b and 6 c. The top boards 6 a, 6 band 6 c and bottom boards are connected to the pallet stringers 7 a, 7 band 7 c. The bottom boards of the pallet 5 contact the wheel assemblies30. Of course, the invention is not limited by the type of palletutilized.

The track sub-assemblies 2 l, 2 c and 2 r are identical in construction.Therefore, only one track sub-assembly 2 l will be described in furtherdetail. It should be understood that track sub-assemblies 2 c and 2 rinclude the same elements shown and described with respect to tracksub-assembly 2 l.

As shown in FIGS. 2 and 3, the track frame 10 of track sub assembly 2 lincludes a first, or left profile 11 a and a second, or right profile 11b, which are fastened together in a spaced relationship by threadedfastening rods 20. Profiles 11 a and 11 b are supported by the supportstructure. As shown in FIGS. 3-9, profiles 11 a and 11 b are identicalin construction. However, profiles 11 a and 11 b are installed inopposite orientations, as can be seen in FIG. 3. The profiles 11 a and11 b are fastened together in spaced relationship, forming a channel 15between them. Profiles 11 a and 11 b preferably comprise enhancedC-channel members constructed from galvanized steel, but may beconstructed from other suitable parts and/or materials. As shown inFIGS. 3 and 6, the profile 11 a includes a vertical section 12 a, abottom leg 13 a connected to a bottom part of vertical section 12 a andan upper leg 14 a connected to a top part of vertical section 12 a.Similarly, as shown in FIGS. 3 and 9, profile 11 b includes a verticalsection 12 b, a bottom leg 13 b connected to a bottom part of verticalsection 12 b and an upper leg 14 b connected to a top part of verticalsection 12 b. The lower legs 13 a and 13 b and upper legs 14 a and 14 bextend away from the channel 15 in a direction substantiallyperpendicular to the length of the profiles 11 a and 11 b. The lowerlegs 13 a and 13 b extend wider in a direction perpendicular to thelength of the profiles 11 a and 11 b than the upper legs 14 a and 14 bdo, in order to provide a wide support base for the profiles 11 a and 11b.

A longitudinal row of bottom leg mounting holes 19 a and 19 b (shownbest in FIGS. 5 and 8) is provided in the lower legs 13 a and 13 b,respectively, for mounting each profile 11 a and 11 b to the supportstructure. The top legs 14 a and 14 b extend away from the channel 15 tocover mounting hardware for the wheel assemblies 30, which are describedin following paragraphs. Referring now to FIGS. 4, 6, 7 and 9, eachchannel section 12 a and 12 b further includes a longitudinal row ofupper profile mounting holes 17 a and 17 b, respectively, and alongitudinal row of lower profile mounting holes 18 a and 18 b,respectively. The lower profile mounting holes 18 a and 18 b aredisposed below and longitudinally offset from the respective upperprofile mounting holes 17 a and 17 b, such that upper profile mountingholes 17 a and 17 b and lower profile mounting holes 18 a and 18 b aredisposed along the length of the respective profiles 11 a and 11 b inalternating fashion. As shown in FIG. 3, the profile mounting holes 17 aand 18 a of the profile 11 a are aligned with profile mounting holes 17b and 18 b of the profile 11 b. As illustrated in FIGS. 2 and 3, thethreaded rods 20 are fastened between selected corresponding pairs ofupper profile mounting holes 17 a and 17 b and lower profile mountingholes 18 a and 18 b to secure the profiles 11 a and 11 b to each other.Spacers 22 are mounted on the rods 20 to stabilize the profiles 11 a and11 b, and to maintain proper spacing between the profiles 11 a and 11 b.Preferably, the threaded fastening rods 20 are fastened betweencorresponding pairs of upper profile mounting holes 17 a and 17 b andcorresponding pairs of lower profile mounting holes 18 a and 18 b inalternating fashion as indicated in FIG. 2.

The channel sections 12 a and 12 b further include axle mounting holes16 a and 16 b as shown in FIGS. 3, 4, 6, 7 and 9. The axle mountingholes 16 a and 16 b are disposed in a longitudinal row along the channelsections 12 a and 12 b, respectively. The axle mounting holes 16 a ofprofile 11 a are aligned with the axle mounting holes 16 b of profile 11b for receiving axles of wheel assemblies 30. The wheel assemblies 30will now be described in greater detail.

A wheel assembly 30 is shown in FIG. 3. Each wheel assembly 30 includesan axle 31 and a polycarbonate resin wheel 37 rotatably mounted on theaxle 31. As shown in FIG. 3, each axle 31 includes a shaft portion 32, ahead portion 33 adjacent one end of the shaft portion 31 and a threadedend portion 34 adjacent a second end of the shaft. Axles 31 arepreferably constructed from steel, but may be constructed from anothersuitable metal. Each axle 31 further comprises a lubricant coating 35that is fixed to and bonded with the shaft portion 32. Preferably, thecoating 35 is fluorocarbon-based or Teflon-based and is heated to a hightemperature to fix to and bond with the shaft portion 32. Each axle 31extends between profiles 11 a and 11 b transverse to the track flowdirection. The head portion 33 and threaded end portion 34 of each axle31 are mounted within an axle mounting holes 16 a and 16 b,respectively. A nut 36 engages the threaded end portion 34 of each axle31 and works in conjunction with the head portion 33 to secure the axle31 between axle holes 16 a and 16 b.

A preferred embodiment of a wheel 37 is shown in FIGS. 10-16. Referringto FIGS. 10-11, wheel 37 is formed as a unitary body and is constructedof a polycarbonate-based resin impregnated with a lubricant. That is, apolycarbonate-based resin is mixed with a lubricant to form the wheel37. Preferably, the polycarbonate-based resin is impregnated with alubricant comprising silicone and/or molybdenum. One example of anacceptable material is that known as PC/PET 325,manufactured/distributed by B&M Plastics, which has been impregnatedwith a lubricant comprising silicone and molybdenum. The wheel 37includes a substantially cylindrical hub 39 coaxial with a rotationalaxis X of the wheel 37, a rim 43 concentric with the hub, and a web 47connecting the hub 39 to the rim 43. The wheel 37 may further includemultiple ribs 51 a and 51 b connecting the hub 39 to the rim 43 throughthe web 47. The ribs 51 a and 51 b are optionally provided to strengthenthe wheel 37. The hub 39 includes an outer circumferential surface 40connected to the web 47 at a hub-web junction 48 (shown in FIGS. 10, 11and 14), and a passage 41 for receiving an axle 31 and allowing thewheel 37 to rotate about the axle 31. The rim 43 comprises an innercircumferential surface 44 connected to the web at a rim-web junction 49(shown in FIGS. 10, 11, 13 and 14) and an outer circumferential surface,or tread surface 45 for contacting the pallet 5.

Referring to FIGS. 12 and 13, the hub 39 has a hub width W1 measuredalong a line parallel to the rotational axis X. The rim 43 has a rimwidth W2 that is measured along a line parallel to the rotational axisX. The hub width W1 is slightly greater than the rim width W2. Accordingto an exemplary embodiment of the invention, the hub width W1 isapproximately 1.165 inches and the rim width W2 is approximately 1.125inches. Thus, the hub 39 and rim 43 are wider than the hubs and rims ofprior art skate wheels. Referring to FIGS. 12 and 13, the web 47 extendsfrom the hub 39 to the rim 43 along a wheel center plane C that isperpendicular to the rotational axis X and that bisects the width W1 ofthe hub. The wheel center plane C bisects the wheel 37 into a first, orleft wheel side 38 a to the left of the center plane C and a second, orright wheel side 38 b to the right of the center plane C. As shown inFIGS. 10-14, the hub 39 includes a first, or left end 42 a and a second,or right end 42 b on the left and right wheel sides 38 a and 38 b,respectively. The rim 43 includes a first, or left rim edge 46 a and asecond, or right rim edge 46 b on the left and right sides 38 a and 38b, respectively. Referring to FIGS. 10 and 11, the web 47 includes afirst, or left web face 50 a on the left side 38 a and a second, orright web face 50 b on the right side 38 b.

As shown in FIGS. 15 and 16, the hub 39 has an inner diameter D1 and anouter diameter D2, and the rim 43 has an inner diameter D3 and an outerdiameter D4. The outer diameter D4 may also be referred to as the “wheeldiameter”. According to an exemplary embodiment of the invention, thediameters D1, D2, D3 and D4 are approximately 0.317 inches, 0.563inches, 1.700 inches and 1.900 inches, respectively. Thus, the wheel 37has a smaller outer diameter (i.e., rim outer diameter D4) than priorart skate wheels.

Referring now to FIGS. 10-11, and 13-16, each side 38 a and 38 b ofwheel 37 can include multiple ribs 51 a and 51 b, respectively.According to the exemplary embodiment of the wheel 37 shown in FIGS.10-16, sides 38 a and 38 b each comprise eight ribs 51 a and 51 b,respectively. However, each side 38 a and 38 b may comprise any numberof ribs 51 a and 51 b, respectively, as is required to support loadstransported by the track system 1. The load capacity of the exemplarywheel 37 ranges from 225 pounds of dynamic load to 538 pounds of staticload. However, increasing the number of ribs 38 a and 38 b andincreasing the hub width W2 and rib width W2 can increase the loadcapacity of the wheel 37. As shown in FIGS. 10-11, each rib 51 aincludes a first leg 52 a extending on the outer circumferential surface40 of the hub from the left end 42 a of the hub 39 to the hub-webjunction 48, a second leg 53 a extending on the left web face 50 a fromthe hub-web junction 48 to the rim-web junction 49, and a third leg 54 aextending on the inner circumferential surface 44 of the rim 43 from therim-web junction 49 to the left rim edge 46 a. Each rib 51 b includes afirst leg 52 b extending on the outer circumferential surface 40 of thehub from the right hub end 42 b to the hub-web junction 48, a second leg53 b extending on the right web face 50 b from the hub-web junction 48to the rim-web junction 49, and a third leg 54 b extending on the innercircumferential surface 44 of the rim 43 from the rim-web junction 49 tothe right rim edge 46 b.

Referring to FIGS. 14-16, ribs 51 a on the left side 38 a of the wheel37 are disposed at selected angular locations about the rotational axisX and are spaced apart by an inter-rib angle .theta. (shown in FIG. 14)measured about the rotational axis X. Cavities 55 a are defined betweenconsecutive ribs 51 a. Optionally, raised identification letters 56 maybe formed on web face 50 a within a cavities 55 a. Although not shown,letters 56 may also be formed on web face 50 b. Referring again to FIGS.14-16, the ribs 51 b on the right side 38 b of the wheel 37 are disposedat selected angular locations about the rotational axis X, andconsecutive ribs 51 b are spaced apart by the inter-rib angle .theta.(shown in FIG. 14) measured about the rotational axis X. Cavities 55 bare defined between consecutive ribs 51 b. However, as is shown in FIGS.13-16, the ribs 51 b and cavities 55 b are offset from ribs 51 a andcavities 55 a by an offset angle .phi. measured about the rotationalaxis. In other words, the ribs 51 a on the left side 38 a do notdirectly oppose ribs 51 b on the right side 38 b. According to anexemplary embodiment of the invention in which each wheel side 38 a and38 b comprises eight ribs 51 a and 51 b, the optimum offset angle .phi.is approximately 22.5 degrees, as is shown in FIG. 14 and is reflectedin FIGS. 15-16. Offsetting the ribs 51 a and cavities 55 a with respectto the ribs 51 b and cavities 55 b places a rib 51 a on the wheel side38 a at a radial angular location corresponding to the middle of acavity 55 b on wheel side 38 b, and places a rib 51 b on the wheel side38 b at a radial angular location corresponding to the middle of acavity 55 a on wheel side 38 a. This structure approximately doubles thestrength of the wheel 37 with respect to the strength of a similar wheelhaving directly opposed ribs/cavities on opposite sides of the wheel.

The freewheel flow track system 1 is capable of supporting heavypallets, and allows for efficient and reliable pallet flow. The wheels37 are constructed of self-lubricating polycarbonate resin and do notinclude ball bearings, making them resistant to corrosion. Thus, thefreewheel flow track system 1 is suitable for heavy-duty pallet flowapplications in FDA wash down compliant facilities.

FIGS. 17-19 show cut-away views of a freewheel flow track system 101according to another embodiment of the invention. Freewheel flow tracksystem 101 includes a track assembly 102. Referring to FIGS. 17 and 18,the track assembly 102 supports a pallet 5 and includes an entrance end103 and an exit end 104. Products supported by the track assembly 102are transported in a track flow direction extending from the entranceend 103 to the exit end 104. As shown in FIG. 17, the track assembly 102includes track sub-assemblies 102 l, 102 c and 102 r. Tracksub-assemblies 102 l, 102 c and 102 r each include a track frame 10 andwheel assemblies 80 mounted to the respective track frame 10. The wheelassemblies 80 of each track sub assembly 102 l, 102 c and 102 r arearranged in a row extending from the entrance end 103 to the exit end104. Thus, the track sub-assemblies 102 l, 102 c and 102 r are similarto the track sub assemblies 2 l, 2 c and 2 r, except that the tracksub-assemblies 102 l, 102 c and 102 r include wheel assemblies 80instead of the wheel assemblies 30. Since track sub-assemblies 102 l,102 c and 102 r comprise the same components, only one tracksub-assembly 102 l will be described in further detail. It should beunderstood that the following description of track sub-assembly 102 lapplies to track sub-assemblies 102 c and 102 r as well.

Track frame 10 of track sub-assembly 102 l is described in the firstembodiment of the invention and shown in FIGS. 1-9. A wheel assembly 80is shown in detail in FIG. 19. Each wheel assembly 80 includes an axle81 and a polycarbonate resin wheel 37 rotatably mounted on the axle 81.A wheel 37 is described in the first embodiment of the invention and isshown in FIGS. 10-16. As shown in FIG. 19, each axle 81 includes a shaftportion 82, a first dimpled end portion 88 a at one end of the shaftportion 82 and a second dimpled end portion 88 b at an opposite end ofthe shaft portion. The dimpled end portions 88 a and 88 b are of areduced diameter that is smaller than the diameter of the axle mountingholes 16 a and 16 b and the diameter of shaft portion 82. Axles 81 arepreferably constructed from steel, but may be constructed from anothersuitable metal. with the axles 81 comprise a lubricant coating 85 thatis fixed to and bonded with the shaft portion 82. Preferably, thecoating 85 is fluorocarbon-based or Teflon-based, and is heated to ahigh temperature to fix to and bond with the shaft portion 82. Thedimpled ends 88 a and 88 b are mounted within and loosely engage theaxle mounting holes 16 a and 16 b, respectively, within the profiles 11a and 11 b of the track frame 10.

The freewheel flow track system 101 provides the features and advantagesof the embodiment of FIGS. 1-16. However, in addition to those featuresand advantages, the axles 81 of freewheel flow track system 101 are ableto rotate within the track frame 101 and may be easily inserted in andremoved from the track frame 10.

FIGS. 20-28 show cut-away views of a freewheel flow track system 201according to yet another embodiment of the invention. Freewheel flowtrack system 201 includes track assembly 202. As shown in FIGS. 20 and21, the track assembly 202 supports a pallet 5 and includes an entranceend 203 and an exit end 204. Products supported by the track assembly202 are transported in a track flow direction extending from theentrance end 203 to the exit end 204. Referring to FIG. 20, the trackassembly 202 comprises track sub-assemblies 202 l, 202 c and 202 r.Track sub-assemblies 202 l, 202 c and 202 r each include a track frame60 and wheel assemblies 30 mounted to the respective track frame 60. Thewheel assemblies 30 of each sub assembly 202 l, 202 c and 202 r arearranged in a longitudinal row extending from the entrance end 203 tothe exit end 204. Thus, the track sub-assemblies 202 l, 202 c and 202 rare similar to the track sub-assemblies 2 l, 2 c and 2 r, except thatthe track sub-assemblies 202 l, 202 c and 202 r include track frames 60instead of track frames 10. Track sub-assemblies 202 l, 202 c and 202 rcomprise the same components. Therefore, only one track sub-assembly 202l will be described in further detail. It should be understood that thefollowing description of track sub-assembly 202 l also applies to tracksubassemblies 202 c and 202 r.

The track frame 60 of the track sub-assembly 202 l comprises profiles 61a and 61 b. The profiles 61 a and 61 b are fastened together in spacedrelationship, forming a channel 15 between them. As shown in FIGS.22-28, profiles 61 a and 61 b are identical in construction. However,profiles 61 a and 61 b are installed in track frame 60 l in oppositeorientations, as can be seen in FIG. 22. Profiles 61 a and 61 bpreferably comprise C-channel members constructed from galvanized steel,but may be constructed from other suitable parts and/or materials. Asshown in FIGS. 22-25, the profile 61 a includes a vertical section 62 a,a bottom leg 63 a connected to a bottom part of vertical section 62 aand an upper leg 64 a connected to a top part of vertical section 62 a.Similarly, as shown in FIGS. 22 and 26-28, the profile 61 b includes avertical section 62 b, a bottom leg 63 b connected to a bottom part ofvertical section 62 b and an upper leg 64 b connected to a top portionof vertical section 62 b.

The lower legs 63 a and 63 b and upper legs 64 a and 64 b extend awayfrom the channel 15 in a direction substantially perpendicular to thelength of the profiles 61 a and 61 b, and may be mounted to anunderlying support structure (not shown) using known mounting elementsand methods. The top legs 64 a and 64 b extend away from the channel 15to cover mounting hardware for the wheel assemblies 30, which aredescribed in following paragraphs. As shown in FIGS. 21-23, 25, 26 and28, each channel section 62 a and 62 b further includes a respectivelongitudinal row of upper profile mounting holes 67 a and 67 b and arespective longitudinal row of lower profile mounting holes 68 a and 68b. The lower profile mounting holes 68 a and 68 b are disposed below andlongitudinally offset from the respective upper profile mounting holes67 a and 67 b, such that upper profile mounting holes 67 a and 67 b andlower profile mounting holes 68 a and 68 b are disposed along the lengthof the respective profiles 61 a and 61 b in alternating fashion.Referring to FIG. 22, the profile mounting holes 67 a and 68 a of theprofile 61 a are aligned with profile mounting holes 67 b and 68 b,respectively, of the profile 61 b. As illustrated in FIGS. 21 and 22,threaded rods 20 are fastened between selected corresponding pairs oflower profile mounting holes 68 a and 68 b. As shown in FIG. 22, spacers22 are mounted on threaded rods 20 to stabilize the profiles 61 a and 61b and to maintain proper spacing between the profiles 61 a and 61 b.Preferably, threaded rods 20 are fastened between corresponding pairs ofupper profile mounting holes 17 a and 17 b and corresponding pairs oflower profile mounting holes 18 a and 18 b in alternating fashion asindicated in FIG. 21.

The channel sections 62 a and 62 b further include respective axlemounting holes 66 a (shown in FIGS. 21-23 and 25) and 66 b (shown inFIGS. 22, 26 and 28). The axle mounting holes 66 a and 66 b are disposedin a longitudinal row along the respective channel sections 62 a and 62b, respectively. The axle mounting holes 66 a of profile 61 a arealigned with the axle mounting holes 66 b of profile 61 b for receivingthe axles 31 of wheel assemblies 30.

Each axle 31 extends between profiles 61 a and 61 b transverse to thetrack flow direction. The head portion 33 and threaded end portion 34 ofeach axle 31 are mounted within an axle mounting holes 66 a and 66 b,respectively. A nut 36 engages the threaded end portion 34 of each axle31 and works in conjunction with the head portion 33 to secure the axle31 between axle holes 66 a and 66 b.

Thus, freewheel flow track system 201 is similar to freewheel flow tracksystem 1, except that freewheel flow track system 201 includes profiles61 a and 61 b in the place of profiles 11 a and 11 b. Profiles 61 a and61 b comprise C-channels having narrower bottom legs 63 a and 63 b thanthe bottom legs 13 a and 13 b of profiles 11 a and 11 b. Profiles 61 aand 61 b also lack the bottom leg mounting holes 19 a and 19 b ofprofiles 11 a and 11 b. Therefore, the profiles 61 a and 61 b aresimpler and more cost-effective to manufacture than profiles 11 a and 11b are. However, profiles 11 a and 11 b can support heavier loads thanprofiles 61 a and 61 b can.

FIGS. 29-31 show a freewheel track system 301 according to anotherembodiment of the invention. The freewheel track system 301 includes atrack assembly 302. The track assembly 302 includes an entrance end 303and an exit end 304, and comprises track sub-assemblies 302 l, 302 c and302 r. Products supported by the track assembly 302 are transported in atrack flow direction extending from the entrance end 303 to the exit end304. Each track sib-assembly includes a track frame 60 and multiplewheel assemblies 80 mounted to the respective track frame. The wheelassemblies 80 of each sub-assembly 302 l, 302 c and 302 r are arrangedin a row extending from the entrance end 303 to the exit end 304. Sincetrack sub-assemblies 302 l, 302 c and 302 r identical in construction,only one track sub-assembly 302 l will be further described. It shouldbe understood that track sub-assemblies 302 c and 302 r include the sameelements disclosed in the description of track sub-assembly 302 l.

The track frame 60 is described in full with respect to the embodimentof FIGS. 20-28. A wheel assembly 80 is fully described in the embodimentshown in FIGS. 17-19. As shown in FIG. 31, the track sub-assembly 302 lis assembled by mounting the axles 81 of the wheel assemblies 80 betweenthe profiles 61 a and 61 b of track frame 60. More particularly, thedimpled ends 88 a and 88 b of axles 81 are mounted within and engageaxle mounting holes 66 a and 66 b, respectively. The profiles 61 a and61 b of this embodiment of the invention are cost-effective tomanufacture. Furthermore, the axles 81 rotate within the track frame 60and can easily be installed in and removed from the track frame 60.

FIGS. 32-34 show a freewheel flow track system 401 according to yetanother embodiment of the invention. Freewheel flow track system 401 isparticularly well-suited for directly supporting cartons. FIG. 32 showsa cut-away view of the freewheel flow track system 401 including a widetrack assembly 402 having an entrance end 403 and an exit end 404.Products supported by the track assembly 402 are transported in a trackflow direction extending from the entrance end 403 to the exit end 404.The track assembly 402 is supported by an underlying support structure(not shown), typically (though not necessarily) in an inclinedorientation. The track assembly 402 comprises a longitudinally extendingtrack frame 410 extending from the entrance end 403 to the exit end 404,and wheel assemblies 430 mounted b the track frame 410 for maintainingrolling engagement with a carton 405. The wheel assemblies 430 arearranged in a row extending from the entrance end 403 to the exit end404.

Referring to FIGS. 32 and 33, a carton 405 is shown supported by thetrack assembly 402. The carton 405 comprises a box that isrepresentative of cartons commonly used in picking applications. Abottom panel (not shown) of the carton 405 contacts the wheel assemblies430.

As shown in FIGS. 32 and 34, the track frame 410 includes a first, orleft profile 11 a and a second, or right profile 11 b, which arefastened together in a spaced relationship by long threaded fasteningrods 420. The profiles 11 a and 11 b are supported by the supportstructure. The profiles 11 a and 11 b are fastened together in spacedrelationship, forming a relatively wide channel 415 between them. Thatis, the width of the channel 415 is greater than the width of the carton405. Profiles 11 a and 11 b are fully described in previous embodimentsof the invention with reference to FIGS. 19-25. As in previousembodiments of the invention, profiles 11 a and 11 b are installed inopposite orientations, as can be seen in FIG. 34.

As illustrated in FIG. 34, the upper profile mounting holes 17 a andlower profile mounting holes 18 a of profile 11 a are aligned with theupper profile mounting holes 17 b and lower profile mounting holes 18 bof profile 11 b. As shown in FIGS. 33 and 34, the threaded rods 420 arefastened between selected corresponding pairs of lower profile mountingholes 18 a and 18 b. However, in alternative embodiments of theinvention, threaded rods 420 may be fastened between selected pairs ofupper profile mounting holes 17 a and 17 b and/or lower profile mountingholes 18 a and 18 b as is necessary to secure the profiles 11 a and 11 bto each other. The axle mounting holes 16 a of profile 11 a are alignedwith the axle mounting holes 16 b of profile 11 b for receiving axles ofwheel assemblies 430. A description of wheel assemblies 430 follows.

A wheel assembly 430 is shown in detail in FIG. 34. As shown in FIG. 34,each wheel assembly 430 includes a multi-wheel axle 431 and multiplepolycarbonate resin wheels 37 rotatably mounted on the axle 431. Thewheels 37 of a given wheel assembly 430 are mounted along the axle 431in a row extending transverse to the track flow direction. A wheel 37 isshown in FIGS. 10-16 and is fully described in the first embodiment ofthe invention with reference to FIGS. 10-16. As shown in FIG. 34, eachaxle 431 includes a shaft potion 432, a head portion 433 adjacent oneend of the shaft portion and a threaded end portion 434 adjacent asecond end of the shaft portion. Axles 431 are preferably constructedfrom steel, but may be constructed from another suitable metal. Theshaft portions 432 are coated with a lubricant coating 435 that is fixedto and bonded with the shaft portion 432. Preferably, the coating 435 isfluorocarbon-based or Teflon-based, and is heated to a high temperatureto fix to and bond with the shaft portion 432. Each axle 431 extendsbetween profiles 11 a and 11 b transverse to the track flow direction.The head portion 433 and threaded end portion 434 of each axle 431 aremounted within axle mounting holes 16 a and 16 b, respectively. A nut436 engages the threaded end portion 434 of each axle 431 and works inconjunction with the head portion 433 to secure the axle 431 betweenaxle holes 116 a and 116 b.

The wheel assembly 430 further includes a plurality of axle spacers 450.Axle spacers 450 are mounted on the axle 431 between consecutive wheels37 in the assembly 430 and secure the wheels 37 in a desired positionalong the axle 431. Various numbers of spacers 450 and spacers 450 ofvarying sizes may be used in each wheel assembly, and the arrangement ofthe spacers 450 and wheels 37 in a wheel assembly 430 may be varied tochange the position of the wheels 37 along the axle 431. The spacers 450include spacer slits 451 to allow the spacers 450 to be snapped onto andoff of the axle 431, thereby facilitating the task of changing thepositions of the wheels 37 along the axle 431. As shown in FIG. 32,wheels 37 within a given wheel assembly 430 occupy unique transversepositions with respect to the wheels 37 of adjacent wheel assemblies430, wherein the transverse positions are measured in the directiontransverse to the track flow direction. Positioning the wheels 37 inthis manner generally enables more wheels to contact the bottom of acarton 405.

The wide track assembly 402 provides high load capacity for supportingheavy cartons and provides reliable and efficient carton flow throughthe use of the wheel assemblies 430, which each comprise a row ofmultiple polycarbonate wheels 37 extending transverse to the track flowdirection.

Yet another embodiment of the invention is shown in FIGS. 35-37. Asshown in FIGS. 35 and 36, freewheel flow track system 501 comprisestrack assembly 502 having an entrance end 503 and an exit end 504.Products supported by the track assembly 502 are transported in a trackflow direction extending from the entrance end 503 to the exit end 504.The flow track system 502 is shown supporting a carton 405. Trackassembly 502 includes track frame 410 and wheel assemblies 480 mountedto the track frame 410. The wheel assemblies 480 are arranged in a rowextending from the entrance end 503 to the exit end 504. The track frame410 is fully described in the embodiment of FIGS. 32-34.

As shown in FIG. 37, wheel assemblies 480 are similar to wheelassemblies 430, with the exception of multi-wheel axles 481. The axles481 each include a shaft portion 482, a first dimpled end portion 488 aadjacent one end of the shaft portion 482 and a second dimpled endportion 488 b adjacent a second end of the shaft portion 482. Axles 481are preferably constructed from steel, but may be constructed fromanother suitable metal. The shaft portions 482 are coated with alubricant coating 485 that is fixed to and bonded with the shaft portion482. Preferably, the coating 485 is fluorocarbon-based or Teflon-based,and is heated to a high temperature to fix to and bond with the shaftportion 482. Axles 481 extend between profiles 11 a and 11 b transverseto the track flow direction. As shown in FIG. 35, wheels 37 within agiven wheel assembly 480 occupy unique transverse positions with respectto the wheels 37 of adjacent wheel assemblies 480, wherein thetransverse positions are measured in the direction transverse to thetrack flow direction. The dimpled end portions 488 a and 488 b aremounted within and engage axle mounting holes 16 a and 16 b,respectively, of profiles 11 a and 11 b. Thus, the axles 481 are able torotate within the track frame 410 and may be easily inserted in andremoved from the frame 410.

FIGS. 38-40 show a freewheel flow track system 601 according to anotherembodiment of the invention. As shown in FIGS. 38 and 39, freewheel flowtrack system 601 comprises a track assembly 602 having an entrance end603 and an exit end 604. Products supported by the track assembly 602are transported in a track flow direction extending from the entranceend 603 to the exit end 604. The track assembly 602 is shown supportinga carton 405. Track assembly 402 includes a track frame 460 and wheelassemblies 430 mounted to the frame 460. The wheel assemblies 430 arearranged in a row extending from the entrance end 603 to the exit end404. Track frame 460 includes profiles 61 a and 61 b, which are shown ingreater detail in FIGS. 23 to 28 and are fully described in previousembodiments of the invention. The profiles 61 a and 61 b are fastenedtogether in spaced relationship, forming a channel 415 between them.More particularly, referring to FIG. 40, the profile mounting holes 67 aand 68 a of the profile 61 a are aligned with corresponding profilemounting holes 67 b and 68 b, respectively, of the profile 61 b. Asillustrated in FIGS. 39 and 40, threaded rods 420 are fastened betweenselected corresponding pairs of lower profile mounting holes 68 a and 68b, but may be fastened between any selected pairs of upper profilemounting holes 67 a and 67 b and/or pairs of lower profile mountingholes 68 a and 68 b. Axles 431 extend between profiles 61 a and 61 btransverse to the track flow direction, and are mounted within axlemounting holes 66 a and 66 b. As shown in FIG. 38, wheels 37 within agiven wheel assembly 430 occupy unique transverse positions with respectto the wheels 37 of adjacent wheel assemblies 430, wherein thetransverse positions are measured in the direction transverse to thetrack flow direction. Due to the use of profiles 61 a and 61 b in placeof profiles 11 a and 11 b, the freewheel system 601 is morecost-effective to manufacture than systems 401 and 501, however it isnot as well-suited for supporting heavy cartons.

Yet another embodiment of the invention is shown in FIGS. 41-43. FIG. 37shows a freewheel flow track system 701 including track assembly 702having an entrance end 703 and an exit end 704. Products supported bythe track assembly 702 are transported in a track flow directionextending from the entrance end 703 to the exit end 704. The trackassembly 702 is shown supporting a carton 405. As illustrated in FIGS.41-43, the track assembly 702 includes a track frame 460 and wheelassemblies 480 mounted to the track frame 460. The wheel assemblies 480are arranged in a row extending from the entrance end 703 to the exitend 704. As described with respect to the embodiment of FIGS. 38-40, thetrack frame 460 includes profiles 61 a and 61 b. As described in theembodiment of FIGS. 35-37, the wheel assemblies 480 include axles 481,wheels 37 and spacers 450 mounted on axles 481. This embodiment of theinvention is achieved by mounting the wheel assemblies 480 to profiles61 a and 61 b. More specifically, as shown info FIG. 43, axles 481extend between profiles 61 a and 61 b transverse to the track flowdirection, and dimpled end portions 88 a and 88 b are mounted withinaxle mounting holes 66 a and 66 b, respectively. As shown in FIG. 41,wheels 37 within a given wheel assembly 480 occupy unique transversepositions with respect to the wheels 37 of adjacent wheel assemblies480, wherein the transverse positions are measured in the directiontransverse to the track flow direction. This embodiment of the inventioncombines cost-effective profiles 61 a and 61 b with axles 481 that areeasily insertable in and removable from track frame 460.

It will be understood by those skilled in the art that while theforegoing invention has a been disclosed with reference to preferredembodiments or features, various modifications, changes and additionscan be made to the foregoing invention without departing from the spiritand scope of the invention as set forth in the following claims.

1. A conveyor system comprising: a track assembly comprising a first frame member and a second frame member, the frame members spaced apart from each other; and a wheel assembly comprising an axle and a plurality of wheels, the axle extending between the frame members, each wheel rotatably mounted to the axle, each wheel comprising: a central hub, a rim concentric with the hub, a web extending between the hub and the rim, a first set of ribs positioned on a first side of the wheel, and a second set of ribs positioned on a second side of the wheel, the second set of ribs offset from the first set of ribs by an offset angle.
 2. The conveyor system of claim 1, wherein the axle is at least partially coated in a lubricant coating.
 3. The conveyor system of claim 2, wherein the lubricant coating is bonded to the axle.
 4. The conveyor system of claim 2, wherein the lubricant coating comprises at least one of the following materials: a fluorocarbon-based lubricant or a Teflon-based lubricant.
 5. The conveyor system of claim 1, wherein at least one of the wheels comprises a polycarbonate-based resin.
 6. The conveyor system of claim 5, wherein the polycarbonate-based resin is impregnated with a lubricant.
 7. The conveyor system of claim 6, wherein the lubricant comprises at least one of the following materials: silicone and molybdenum.
 8. The conveyor system of claim 1, wherein at least one of the wheels comprises PC/PET
 325. 9. The conveyor system of claim 1, wherein each rib is spaced apart by an inter-rib angle such that cavities are defined between consecutive ribs.
 10. The conveyor system of claim 1, wherein each rib comprises: a first leg extending from the hub to an intersection of the hub and the web; a second leg extending across the web; and a third leg extending from an intersection of the web and the rim to the rim.
 11. The conveyor system of claim 1, wherein the axle comprises a first end portion associated with the first frame member and a second end portion associated with the second frame member, the first end portion comprising a first dimple that engages a first axle mounting hole in the first frame member.
 12. The conveyor system of claim 11, wherein the second end portion comprises a second dimple that engages a second axle mounting hole in the second frame member.
 13. A conveyor system comprising: a track assembly comprising a first frame member and a second frame member, the frame members spaced apart from each other; a wheel assembly comprising an axle and a plurality of wheels, the axle extending between the frame members, each wheel rotatably mounted to the axle, each wheel comprising: a central hub, a rim concentric with the hub, a web extending between the hub and the rim, and a plurality of ribs connecting the hub to the rim through the web, each rib comprising a first leg extending from the hub to a hub-web junction, a second leg extending from the hub-web junction to a rim-web junction, and a third leg extending from the rim-web junction to the rim.
 14. A conveyor system comprising: a track assembly comprising a first frame member and a second frame member, the frame members spaced apart from each other; a first wheel assembly comprising: an first axle extending between the frame members, a set of first wheels, the first wheels rotatably mounted to the first axle, the first wheels spaced apart from each other along the first axle; a second wheel assembly comprising: a second axle extending between the frame members, and a set of second wheels, each second wheel rotatably mounted to the second axle, the second wheels spaced apart from each other along the second axle, the second wheels staggered with reference to the first wheels.
 15. The conveyor system of claim 14, wherein the first axle comprises a first end portion associated with the first frame member and a second end portion associated with the second frame member, the first end portion comprising a first dimple that engages a first axle mounting hole in the first frame member.
 16. The conveyor system of claim 15, wherein the second end portion comprises a second dimple that engages a second axle mounting hole in the second frame member.
 17. The conveyor system of claim 14, wherein the first axle is at least partially coated in a lubricant coating.
 18. The conveyor system of claim 17, wherein the lubricant coating is bonded to the first axle.
 19. The conveyor system of claim 14, wherein at least one of the wheels comprises a polycarbonate-based resin.
 20. The conveyor system of claim 19, wherein the polycarbonate-based resin is impregnated with a lubricant. 